1. Field
The present Application for Patent relates to communication and, more particularly, to the providing and managing of communication resources in a wireless communication system.
2. Background
Wireless communication systems are widely deployed and provide communication between and among mobile and fixed communication of various content including, as illustrative example, voice, video, messaging, games, financial data and various data representing and relating to each. A wireless communication system may include multiple-access capability, using various time and frequency multiplexing systems and schemes that allow for sharing of available system resources. Examples of multiple-access systems include Code Division Multiple Access (CDMA) systems, Time Division Multiple Access (TDMA) systems, and Frequency Division Multiple Access (FDMA) systems. Many of these example types of multiple access systems have sub-types such as, for FDMA, Orthogonal FDMA (OFDMA) systems, and Single-Carrier FDMA (SC-FDMA) systems.
A wireless communication system may include a plurality of base stations, each supporting communication for a plurality of terminals, of a number that may vary with time. Communication between a base and a terminal is through links, typically termed as forward links and reverse links The forward link (also known as a “downlink”) typically refers to the communication link(s) from the base station to the terminal, and the reverse link (also known as an “uplink”) typically refers to the communication link from the terminal to the base station. The forward and reverse link(s) may or may not share a common physical channel, may or may not share a common carrier frequency, and may or may not share a common encoding and/or modulation scheme.
A base station may cover a respective geographical area, and geographically adjacent base stations may cover respectively adjacent geographical areas that may, or may not, overlap. A base station may maintain forward links with each of a plurality of terminals, each of which may, or may not be within a geographical area assigned to the base station. Due to various factors, at various times the respective channels for the forward link or reverse link, or both, of one or more of the terminals may have a higher, or lower quality, than the corresponding channels for the forward or reverse link, or both, of one or more of the other terminals.
The various factors that may relate to such differences in channel quality include, but are not limited to, differences of geographical distances between the base station and each of the different terminal, different terrestrial (natural or man made) features along the respective different paths, different atmospheric conditions, and/or different interference sources, either local to the terminals or along the path between the terminal and the base station.
Deployment of wireless relays in wireless communication networks has been considered as one potential remedy or compensation for such differences in channel quality because, in theory, potential benefits that have been identified as possible include a broadening or extension of coverage, and an increase in channel capacity.
However, although potential benefits of wireless relays have been seen as possibly significant, various significant problems, both potential and exhibited have been seen as well.
For example, pico cells or femto cells (home NodeBs), which may be viewed as a type of relay, but having only a subset of desired relay functions, have been employed, but these generally require either wired backhaul (such as fiber, cable or DSL) or wireless backhaul over a different wireless technology (e.g. microwave). Femto cells may also have restrictions as to which user equipment (UEs) can associate with them and, further may have considerable additional interference issues. In contrast, desired relays will “self-backhaul”.
Another example of a deployed type of relay is a repeater, which can be considered a sub-class of a relay. Repeaters, as their name implies, repeat signals by receiving a signal, either in the forward link or reverse link, and repeating that received signal. However, repeaters generally amplify and forward an “unclean” copy of signals thus typically amplifying interference and noise as well as useful signal and may be unnecessarily redundant. This low protocol layer level of repeaters also means they generally do not take advantage of different medium and link conditions (channel quality) on different hops.